NASA Hubble Space Telescope Daily Report # 4572

HUBBLE SPACE TELESCOPE DAILY REPORT # 4572

Continuing to collect World Class Science

PERIOD COVERED: UT March 20, 2008 (DOY 080)

OBSERVATIONS SCHEDULED

ACS/SBC 11220

Mapping the FUV Evolution of Type IIn Supernovae

We will use the PR110L prism on the SBC of ACS to map the FUV evolution of Type IIn supernovae {SNe}. The main goal of this proposal is to measure the FUV continuum, Ly-a emission line flux, and their evolution to {1} quantify and interpret Type IIn SN transient event detections at high redshift and {2} dramatically improve current high redshift Type IIn selection criteria. We show that the inherent properties of Type IIn SNe facilitate high redshift detection. We will observe the rest-frame FUV of a sample of eight 0.02 < z < 0.33 Type IIn SNe to directly measure the survival of Ly-alpha photons in low to intermediate redshift Type IIn SNe environments and extrapolate the results to high redshift. We will calibrate relationships such as FUV luminosity vs. emission line flux and measure emission line evolution vs. FUV light evolution. The intent is to categorize and improve the utility of Type IIn SNe.

FGS 11210

The Architecture of Exoplanetary Systems

Are all planetary systems coplanar? Concordance cosmogony makes that prediction. It is, however, a prediction of extrasolar planetary system architecture as yet untested by direct observation for main sequence stars other than the Sun. To provide such a test, we propose to carry out FGS astrometric studies on four stars hosting seven companions. Our understanding of the planet formation process will grow as we match not only system architecture, but formed planet mass and true distance from the primary with host star characteristics for a wide variety of host stars and exoplanet masses. We propose that a series of FGS astrometric observations with demonstrated 1 millisecond of arc per-observation precision can establish the degree of coplanarity and component true masses for four extrasolar systems: HD 202206 {brown dwarf+planet}; HD 128311 {planet+planet}, HD 160691 = mu Arae {planet+planet}, and HD 222404AB = gamma Cephei {planet+star}. In each case the companion is identified as such by assuming that the minimum mass is the actual mass. For the last target, a known stellar binary system, the companion orbit is stable only if coplanar with the AB binary orbit.

NC3 11165

The Radius of the “Super-Neptune” HD 149026b

Current measurements suggest that the transiting exoplanet HD 149026b is a “super-Neptune,” with an enormous heavy-element core. The existence of such a planet is a major challenge to planet formation theories. We propose to place the radius measurement on much firmer footing, by obtaining a NICMOS light curve with 0.4 mmag precision and 13 sec cadence. We will improve the radius measurement by a factor of 2.3, and more importantly, the result will be more robust because we will determine the stellar radius directly from the data. Numerous attempts to do this from the ground have failed.

NIC1/NIC2/NIC3 8795

NICMOS Post-SAA calibration – CR Persistence Part 6

A new procedure proposed to alleviate the CR-persistence problem of NICMOS. Dark frames will be obtained immediately upon exiting the SAA contour 23, and every time a NICMOS exposure is scheduled within 50 minutes of coming out of the SAA. The darks will be obtained in parallel in all three NICMOS Cameras. The POST-SAA darks will be non-standard reference files available to users with a USEAFTER date/time mark. The keyword ‘USEAFTER=date/time’ will also be added to the header of each POST-SAA DARK frame. The keyword must be populated with the time, in addition to the date, because HST crosses the SAA ~8 times per day so each POST-SAA DARK will need to have the appropriate time specified, for users to identify the ones they need. Both the raw and processed images will be archived as POST-SAA DARKSs. Generally we expect that all NICMOS science/calibration observations started within 50 minutes of leaving an SAA will need such maps to remove the CR persistence from the science images. Each observation will need its own CRMAP, as different SAA passages leave different imprints on the NICMOS detectors.

NIC2 11219

Active Galactic Nuclei in nearby galaxies: a new view of the origin of the radio-loud radio-quiet dichotomy?

Using archival HST and Chandra observations of 34 nearby early-type galaxies {drawn from a complete radio selected sample} we have found evidence that the radio-loud/radio-quiet dichotomy is directly connected to the structure of the inner regions of their host galaxies in the following sense: [1] Radio-loud AGN are associated with galaxies with shallow cores in their light profiles [2] Radio-quiet AGN are only hosted by galaxies with steep cusps. Since the brightness profile is determined by the galaxy’s evolution, through its merger history, our results suggest that the same process sets the AGN flavour. This provides us with a novel tool to explore the co-evolution of galaxies and supermassive black holes, and it opens a new path to understand the origin of the radio-loud/radio-quiet AGN dichotomy. Currently our analysis is statistically incomplete as the brightness profile is not available for 82 of the 116 targets. Most galaxies were not observed with HST, while in some cases the study is obstructed by the presence of dust features. We here propose to perform an infrared NICMOS snapshot survey of these 82 galaxies. This will enable us to i} test the reality of the dichotomic behaviour in a substantially larger sample; ii} extend the comparison between radio-loud and radio-quiet AGN to a larger range of luminosities.

NIC2/NIC1/NIC3 11159

The True Galactic Bulge Luminosity Function

We propose to obtain second epoch imaging of the deep Galactic bulge field observed using NICMOS by Zoccali et al. (2000). The bulge luminosity and mass function suffered from 30-50% contamination by foreground disk stars, which was impossible to correct for in the original study. Revisiting the field after 9 years, we propose to segregate the foreground disk stars because they have large transverse velocities, thus revealing the luminosity function of Galactic bulge low mass stars to near the hydrogen burning limit. The slope of the mass function has implications for galaxy formation and for understanding the nature of microlensing in the Galactic bulge.

NIC3 11120

A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic Center

The Galactic center (GC) is a unique site for a detailed study of a multitude of complex astrophysical phenomena, which may be common to nuclear regions of many galaxies. Observable at resolutions unapproachable in other galaxies, the GC provides an unparalleled opportunity to improve our understanding of the interrelationships of massive stars, young stellar clusters, warm and hot ionized gases, molecular clouds, large scale magnetic fields, and black holes. We propose the first large-scale hydrogen Paschen alpha line survey of the GC using NICMOS on the Hubble Space Telescope. This survey will lead to a high resolution and high sensitivity map of the Paschen alpha line emission in addition to a map of foreground extinction, made by comparing Paschen alpha to radio emission. This survey of the inner 75 pc of the Galaxy will provide an unprecedented and complete search for sites of massive star formation. In particular, we will be able to (1) uncover the distribution of young massive stars in this region, (2) locate the surfaces of adjacent molecular clouds, (3) determine important physical parameters of the ionized gas, (4) identify compact and ultra-compact HII regions throughout the GC. When combined with existing Chandra and Spitzer surveys as well as a wealth of other multi-wavelength observations, the results will allow us to address such questions as where and how massive stars form, how stellar clusters are disrupted, how massive stars shape and heat the surrounding medium, and how various phases of this medium are interspersed.

WFPC2 11169

Collisions in the Kuiper belt

For most of the 15 year history of observations of Kuiper belt objects, it has been speculated that impacts must have played a major role in shaping the physical and chemical characteristics of these objects, yet little direct evidence of the effects of such impacts has been seen. The past 18 months, however, have seen an explosion of major new discoveries giving some of the first insights into the influence of this critical process. From a diversity of observations we have been led to the hypotheses that: {1} satellite-forming impacts must have been common in the Kuiper belt; {2} such impacts led to significant chemical modification; and {3} the outcomes of these impacts are sufficiently predictable that we can now find and study these impact-derived systems by the chemical and physical attributes of both the satellites and the primaries. If our picture is correct, we now have in hand for the first time a set of incredibly powerful tools to study the frequency and outcome of collisions in the outer solar system. Here we propose three linked projects that would answer questions critical to the multiple prongs of our hypothesis. In these projects we will study the chemical effects of collisions through spectrophotometric observations of collisionally formed satellites and through the search for additional satellites around primaries with potential impact signatures, and we will study the physical effects of impacts through the examination of tidal evolution in proposed impact systems. The intensive HST program that we propose here will allow us to fully test our new hypotheses and will provide the ability to obtain the first extensive insights into outer solar system impact processes.

WFPC2 11184

Imaging the Shock Precursor in Tycho’s SNR

Cosmic ray acceleration in supernova remnant shocks requires shock precursors where particles are trapped by plasma turbulence. The precursors also heat and compress the upstream gas, producing H alpha emission and affecting line profiles. We propose to image the brightest non-radiative shock in Tycho’s SNR to measure the brightness and width of the precursor. These measurements will constrain 2 key parameters in cosmic ray acceleration models, and they will improve the accuracy of shock speed and electron-ion equilibration derived from H alpha profiles.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of potential non-nominal performance that will be investigated.)

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

                        SCHEDULED      SUCCESSFUL

FGS GSacq               09                  09
FGS REacq               06                  06
OBAD with Maneuver      30                  30

SIGNIFICANT EVENTS: (None)